Effects of Past Global Change on Life (1995)

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GLOBAL CHANGE LEADING TO BIODIVERSITY CRISIS IN A GREENHOUSE WORLD: THE CENOMANIAN-TURONIAN 64 (CRETACEOUS) MASS EXTINCTION levels within the latest Cenomanian extinction interval (discussed in text) support this hypothesis. These new finds suggest at least a partial extraterrestrial origin for late Cenomanian iridium, and for dramatic changes in ocean chemistry associated with some of the major early extinction events in the Cenomanian-Turonian interval. If the shocked quartz, at least, represents a younger Cenomanian terrestrial impact than previously known, for which a crater has not yet been found, a minimal number of five Cenomanian terrestrial impacts is now known, and these predict at least 20 additional aquatic impacts during the Cenomanian impact shower. Is there a linkage among these varied data, their interpretations, and the causal mechanisms of mass extinction, especially the abruptness with which large-scale geochemical fluctuations and correlative extinction events initiate and perpetuate in the late Cenomanian and into the early Turonian? There is a high probability that such a relationship exists, that the C-T mass extinction was multicausal, with meteor/comet impacts into Cenomanian oceans—already highly stratified, largely oxygen-depleted, and rich in sequestered trace elements—causing rapid stirring, overturn, and advection events, and dramatically changing the thermal and chemical regimes of the water column up into the mixing zone. Each successive oceanic impact would set in motion a series of dynamic feedback processes expressed as rapid, large-scale, geochemical and thermal fluctuations such as those associated with individual mass extinction events, or steps, throughout the C-T boundary interval. These ocean-wide perturbations, acting on a largely stenotopic, extinction-prone marine biota, were apparently the direct causes of the ecologically graded C-T extinction events as they progressively exceeded the adaptive ranges of, first, lineages within tropical ecosystems, secondly subtropical to warm temperate lineages, and eventually more temperate lineages. Between impacting events, oceanic feedback processes, perhaps driven independently in part by Milankovitch climate cycles, might continue for perhaps thousands of years, seeking equilibrium. Yet each successive oceanic impact within the Cenomanian shower would reset the perturbation clock, driving extinction for hundreds of thousands of years and, in the end, cumulatively affecting more extinction resistant, temperate ecosystems. This hypothesis best fits the available high-resolution data base for the C-T boundary interval, one of the best-studied mass extinction intervals in the world. However, it is a hypothesis in need of extensive testing, especially in the recognition of impacting events in the deep ocean through sedimentological, paleobiological, and geochemical sensing. Ongoing research on the C-T mass extinction interval thus provides us with an extensive integrated data base, blending sedimentologic, geochemical, and paleobiological data at a level of stratigraphic resolution that equals that of broader-scale (100- to 1000-yr observational scale) Quaternary studies of global change. This study reveals the complex dynamics of change within ocean-climate systems, and biological response to them, at peak development of a greenhouse world—a world toward which we may be heading rapidly as a result of modern global warming and ozone depletion. Of greatest importance is the ability, in older Cretaceous rocks, to develop a timetable for extinction, survival, and recovery spanning one of the major global mass extinctions. From these data, we can develop predictive models, within a high-resolution temporal framework, for other mass extinctions, including the one currently in progress as a result of overpopulation, habitat and ecosystem destruction, and resource depletion at the hands of the human species. It should be of concern to us that modern rates of biodiversity loss exceed the extinction rates of well-studied Cretaceous mass extinctions, including those clearly associated with large bolide impacts. Even more frightening is the prediction from the fossil record that the complex tropical ecosystems, reefs, and rain forests of today, which contain more than half of the global biodiversity, are commonly the first to disappear in ancient mass extinctions and the last to ecologically recover, some 2 to 10 m.y. later (Kauffman and Fagerstrom, 1993). These tropical ecosystems are the harbingers of the mass extinction process and long-term biological crisis on Earth. They alone, once gone, account for enough global biodiversity loss to reach mass extinction levels (>50% of global species). At the rate of global destruction today, tropical rain forests and to a lesser degree tropical reefs will be largely decimated by the year 2500, and certainly by A.D. 3000. Simberloff (1984) estimated that only 2.5% of the neotropical rainforests would remain by 2050, with a resultant loss of more than 50% of the biodiversity of the Western Hemisphere, at current rates of destruction. This may be conservative. Even so, if research on ancient mass extinctions can act as a model for the future of the modern biodiversity crisis, it may be millions of years, without human perturbation, before similar ecosystems will become reestablished in the tropics. Research on ancient mass extinction, survival, and recovery (radiation) intervals can play an important role in understanding the consequences of modern global change phenomena, and in making long-term predictions concerning the present biodiversity crisis-which is already spiraling toward mass extinction levels. REFERENCES Alvarez, W., and R. A. Muller (1984). Evidence from crater ages for periodic impacts in Earth, Nature 308, 718-720. 

GLOBAL CHANGE LEADING TO BIODIVERSITY CRISIS IN A GREENHOUSE WORLD: THE CENOMANIAN-TURONIAN 65 (CRETACEOUS) MASS EXTINCTION Arthur, M. A., W. E. Dean, R. M. Pollastro, G. E. Claypool, and P. A. Scholle (1985). Comparative geochemical and mineralogical studies of two cyclic transgressive pelagic limestone units, Cretaceous Western Interior Basin, U.S., in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 16-27. Barron, E. J. (1993). Atlas of Cretaceous Climate Model Results, Earth System Science Center, Pennsylvania State University, pp. 1-36. Barron, E. J., M. A. Arthur, and E. G. Kauffman (1985). Cretaceous rhythmic bedding sequences—A plausible link between orbital variations and climate, Earth and Planetary Science Letters 72, 327-340. Berner, R. A. (1991). A model for atmospheric CO2 over Phanerozoic time, American Journal of Science 291, 339-376. Berner, R. A. (1994). Geocarb II: A revised model for atmospheric CO2 over Phanerozoic time, American Journal of Science 294, 56-91. Berry, W. B. N., P. Wilde, and M. S. Quinby-Hunt (1990). Late Ordovician mass mortality and subsequent Early Silurian reradiation, in Extinction Events in Earth History, E. G. Kauffman and O. H. Walliser, eds., Springer-Verlag, Berlin, pp. 115-124. Bradley, R. S., ed. (1991). Global Changes of the Past, Office for Interdisciplinary Earth Studies, University Consortium for Atmospheric Research, Boulder, Colo., 514 pp. Caldwell, W. G. E., R. Diner, D. L. Eicher, S. P. Fowler, B. R. North, C. R. Stelck, and L. v.H. Wilhelm (1993). Foraminiferal biostratigraphy of Cretaceous marine cyclothems, in Evolution of the Western Interior Basin, W. G. E. Caldwell and E. G. Kauffman, eds., Geological Association of Canada Special Paper 39, pp. 477-520. Caron, M. (1985). Cretaceous planktic foraminifera, in Plankton Stratigraphy, H. M. Bolli, J. B. Saunders, and K. Perch-Nielsen, eds., Cambridge University Press, Cambridge,pp. 17-86. Cobban, W. A. (1985). Ammonite record from Bridge Creek Member of Greenhorn Limestone at Pueblo Reservoir State Recreation Area, Colorado, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 135-138. Cobban, W. A. (1993). Diversity and distribution of Late Cretaceous ammonites, Western Interior, United States, in Evolution of the Western Interior Basin, W. G. E. Caldwell and E. G. Kauffman, eds., Geological Association of Canada Special Paper 39, pp. 435-451. Cobban, W. A., and G. R. Scott (1972). Stratigraphy and Ammonite Fauna of the Graneros Shale and Greenhorn Limestone near Pueblo, Colorado, U.S. Geological Survey Professional Paper 645, 108 pp. Collom, C. J. (1990). The taxonomic analysis of mass extinction intervals: An approach to problems of resolution as shown by Cretaceous ammonite genera (global) and species (Western Interior of the United States), in Extinction Events in Earth History, E. G. Kauffman and O. H. Walliser, eds., Springer-Verlag, Berlin, pp. 265-276. Eicher, D. L. (1969). Paleobathymetry of Cretaceous Greenhorn Sea in eastern Colorado, American Association of Petroleum Geologists Bulletin 53(5), 1075-1090. Eicher, D. L., and R. Diner (1985). Foraminifera as indicators of water mass in the Cretaceous Greenhorn Sea, Western Interior, in Fine- Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 60-71. Eicher, D. L., and R. Diner (1989). Origin of the Cretaceous Bridge Creek Cycles in the Western Interior, United States, Palaeogeography, Palaeoecology, Palaeoclimatology 74, 127-146. Einsele, G., W. Ricken, and A. Seilacher, eds. (1991). Cycles and Events in Stratigraphy, Springer-Verlag, Berlin, 955 pp. Elder, W. P. (1985). Biotic patterns across the Cenomanian-Turonian extinction boundary, Pueblo, Colorado, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 157-169. Elder, W. P. (1987a). Cenomanian-Turonian (Cretaceous) Stage Boundary Extinctions in the Western Interior of the United States, Unpublished Ph.D. thesis, University of Colorado, Boulder, 660 pp. Elder, W. P. (1987b). The paleoecology of the Cenomanian-Turonian (Cretaceous) stage boundary extinction at Black Mesa, Arizona, Palaios 2, 24-40. Elder, W. P., and J. I. Kirkland (1985). Stratigraphy and depositional environments of the Bridge Creek Limestone Member of the Greenhorn Limestone at Rock Canyon Anticline near Pueblo, Colorado, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 122-134. Fischer, A. G., and M. A. Arthur (1977). Secular variations in the pelagic realm, in Deep-Water Carbonate Environments, H. E. Cook and P. Enos, eds., Society of Economic Paleontologists and Mineralogists Special Publication 25, pp. 19-50. Fischer, A. G., T. Herbert, and I. Premoli Silva (1985). Carbonate bedding cycles in Cretaceous pelagic and hemipelagic sequences, in Fine- Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 1-10. Gale, A. S., H. C. Jenkyns, W. J. Kennedy, and R. M. Cornfield (1993). Chemostratigraphy versus biostratigraphy: Data from 

GLOBAL CHANGE LEADING TO BIODIVERSITY CRISIS IN A GREENHOUSE WORLD: THE CENOMANIAN-TURONIAN 66 (CRETACEOUS) MASS EXTINCTION around the Cenomanian-Turonian boundary, Journal of Geological Society of London 150, 29-32. Glancy, T. J., Jr., M. A. Arthur, E. J. Barron, and E. G. Kauffman (1993). A paleoclimate model for the North American Cretaceous (Cenomanian-Turonian) epicontinental sea, in Evolution of the Western Interior Basin, W. G. E. Caldwell and E. G. Kauffman, eds., Geological Association of Canada Special Paper 39, pp. 219-241. Grieve, R. A. F. (1982). The record of impact on Earth: Implications for a major Cretaceous/Tertiary boundary impact, in Geological Implications of Impacts of Large Asteroids and Comets on the Earth, L. T. Silver and P. H. Schultz, eds., Geological Society of America Special Paper 190, pp. 25-38. Hallam, A. (1984). The causes of mass extinction, Nature 308, 686-687. Hancock, J. M. (1977). The historical development of biostratigraphic correlation, in Concepts and Methods of Biostratigraphy, E. G. Kauffman and J. E. Hazel, eds., Dowden, Hutchinson, and Ross, Stroudsburg, Pa., pp. 3-22. Harries, P. J. (1993). Patterns of Repopulation following the Cenomanian-Turonian (Upper Cretaceous) Mass Extinction, Unpublished Ph.D. thesis, University of Colorado, Boulder, 356 pp. Harries, P. J., and E. G. Kauffman (1990). Patterns of survival and recovery following the Cenomanian-Turonian (Late Cretaceous) mass extinction in the Western Interior Basin, United States, in Extinction Events in Earth History, E. G. Kauffman and O. H. Walliser, eds., Springer-Verlag, Berlin, pp. 277-298. Hattin, D. E. (1971). Widespread, synchronously deposited, burrow-mottled limestone beds in the Greenhorn Limestone (upper Cretaceous) of Kansas and southeastern Colorado, American Association of Petroleum Geologists Bulletin 55, 412-431. Hattin, D. E. (1985). Distribution and significance of widespread, time-parallel pelagic limestone beds in Greenhorn Limestone (upper Cretaceous) of the central Great Plains and southern Rocky Mountains , in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 28-37. Hay, W. W. (1988). Paleoceanography: A review for the GSA centennial, Geological Society of America Bulletin 100, 1934-1956. Hut, P., W. Alvarez, W. P. Elder, T. A. Hansen, E. G. Kauffman, G. Keller, E. M. Shoemaker, and P. R. Weissman (1987). Comet showers as a possible cause of stepwise extinctions, Nature 329, 118-126. Jarvis, I., G. A. Carson, M. K. E. Cooper, M. B. Hart, P. N. Leary, B. A. Tocher, D. Horne, and A. Rosenfeld (1988). Microfossil assemblages and the Cenomanian-Turonian (Late Cretaceous) oceanic anoxic event, Cretaceous Research 9, 3-103. Jeffries, R. P. S. (1961). The paleoecology of the Actinocamax plenus subzone (lower Turonian) in the Anglo-Paris Basin, Palaeontology 4, 609-647. Jeffries, R. P. S. (1963). The stratigraphy of the Actinocamax plenus subzone (Turonian) in the Anglo-Paris Basin, Geological Association of London 74, 1-33. Johnson, C. C., and E. G. Kauffman (1990). Originations, radiations, and extinctions of Cretaceous rudistid bivalve species in the Caribbean Province, in Extinction Events in Earth History, E. G. Kauffman and O. H. Walliser, eds., Springer-Verlag, Berlin, pp. 305-324. Kauffman, E. G. (1975). Dispersal and biostratigraphic potential of Cretaceous benthonic Bivalvia in the Western Interior, in The Cretaceous System in the Western Interior of North America, W. G. E. Caldwell, ed., Geological Association of Canada Special Paper 13, pp. 163-194. Kauffman, E. G. (1984a). The fabric of Cretaceous marine extinctions, in Catastrophes and Earth History—The New Uniformitarianism, W. A. Berggren and J. Van Couvering, eds., Princeton University Press, Princeton, N.J., pp. 151-246. Kauffman, E. G. (1984b). Paleobiogeography and evolutionary response dynamic in the Cretaceous Western Interior Seaway of North America, in Jurassic-Cretaceous Biochronology and Paleogeography of North America, G. E. G. Westermann, ed., Geological Association of Canada Special Paper 13, pp. 273-306. Kauffman, E. G. (1985). Cretaceous evolution of the Western Interior Basin of the United States, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes , L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. iv-xiii. Kauffman, E. G. (1988a). Concepts and methods of high-resolution event stratigraphy, Annual Review of Earth and Planetary Sciences 16, 605-654. Kauffman, E. G. (1988b). The dynamics of marine stepwise mass extinction, in Paleontology and Evolution, Extinction Events, M. Lamolda, E. G. Kauffman, and O. H. Walliser, eds., Review of Espanola Paleontology, n. extraordinario, pp. 57-71. Kauffman, E. G., and W. G. E. Caldwell (1993). The Western Interior Basin in space and time, in Evolution of the Western Interior Basin, W. G. E. Caldwell and E. G. Kauffman, eds., Geological Association of Canada Special Paper 39, pp. 1-30. Kauffman, E. G., and J. A. Fagerstrom (1993). The Phanerozoic evolution of reef diversity, in Species Diversity in Ecological Communities, R. Ricklefs and D. Schluter, eds., University of Chicago Press, Chicago, pp. 315-329. Kauffman, E. G., and B. B. Sageman (1990). Biological sensing of benthic environments in dark shales and related oxygen-restricted facies, in Cretaceous Resources, Events, and Rhythms: Background and Plans for Research, R. N. Ginsburg and B. Beaudoin, eds., Kluwer Academic Publishers, Dordrecht, pp. 121-138. Kauffman, E. G., W. A. Cobban, and D. E. Eicher (1976). Albian through lower Coniacian strata, biostratigraphy, and principal events, Western Interior, United States, in Ann. Mus. d'Hist. Nat. Nice T. IV, G. Thomel and R. Reyment. eds., pp. XXIII.1-XXIII.52. 

GLOBAL CHANGE LEADING TO BIODIVERSITY CRISIS IN A GREENHOUSE WORLD: THE CENOMANIAN-TURONIAN 67 (CRETACEOUS) MASS EXTINCTION Kauffman, E. G., L. M. Pratt, et al. (1985). A field guide to the stratigraphy, geochemistry, and depositional environments of the Kiowa- Skull Creek, Greenhorn, and Niobrara marine cycles in the Pueblo, Canon City area, Colorado, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. FRS-1-FRS-26. Kauffman, E. G., B. B. Sageman, W. P. Elder, and E. R. Gustason (1987). High-resolution event stratigraphy, Greenhorn Cyclothem (Cretaceous: Cenomanian-Turonian), Western Interior Basin of Colorado and Utah, Geological Society of America, Rocky Mountain Section Meeting, Field Guide, Boulder, Colo., 198 PP. Kauffman, E. G., W. P. Elder, and B. B. Sageman (1991). High-resolution correlation: A new tool in chronostratigraphy, in Cycles and Events In Stratigraphy, G. Einsele, W. Ricken, and A. Seilacher, eds., Springer-Verlag, Berlin, pp. 795-819. Kauffman, E. G., B. B. Sageman, J. I. Kirkland, W. P. Elder, P. J. Harries, and T. Villamil (1993). Molluscan biostratigraphy of the Western Interior Cretaceous Basin, in Evolution of the Western Interior Basin, W. G. E. Caldwell and E. G. Kauffman, eds., Geological Association of Canada Special Paper 39, pp. 397-434. Kennedy, W. J. (1971). Cenomanian Ammonites of Southern England, Palaeontology Special Paper 8, 134 pp. Kennedy, W. J., and W. A. Cobban (1991). Stratigraphy and interregional correlation of the Cenomanian-Turonian transition in the Western Interior of the United States near Pueblo, Colorado, a potential boundary stratotype for the base of the Turonian stage, Newsletters on Stratigraphy 24, 1-33. Koch, C. F. (1977). Evolutionary and ecological patterns of upper Cenomanian (Cretaceous) mollusc distribution in the Western Interior of North America, Unpublished Ph.D. thesis, George Washington University, Washington, D.C., v. 1,72 pp. Koch, C. F. (1980). Bivalve species duration, areal extent and population size in a Cretaceous sea, Paleobiology 6, 184-192. Koch, C. F., and J. P. Morgan (1988). On the expected distribution of species ranges, Paleobiology 14, 126-138. Larson, R. L. (1991a). Latest pulse of the Earth; Evidence for a mid-Cretaceous superplume, Geology 19, 547-550. Larson, R. L. (1991b). Geological consequences of superplumes, Geology 19, 963-966. Leckie, R. M. (1985). Foraminifera of the Cenomanian-Turonian boundary interval, Greenhorn Formation, Rock Canyon Anticline, Colorado, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 139-150. Marshall, C. R. (1991). Estimation of taxonomic ranges from the fossil record, in Analytical Paleobiology, N. L. Gilinsky and P. W. Signor, eds., Paleontological Society, Short Courses in Paleontology No. 4, pp. 19-38. McDonough, K. J., and T. Cross (1991). Late Cretaceous sea-level from a paleoshoreline , Journal of Geophysical Research 96, 6591-6607. Melosh, H. J. (1982). The mechanics of large meteoroid impacts in the Earth's oceans, in Geological Implications of Impacts of Large Asteroids and Comets on the Earth, L. T. Silver and P. H. Schultz, eds., Geological Society of America Special Paper 190, pp. 121-128. Obradovich, J. (1993). A Cretaceous time scale, in Evolution of the Western Interior Basin, W. G. E. Caldwell and E. G. Kauffman, eds., Geological Association of Canada Special Paper 39, pp. 379-396. Oeschger, H., and A. Arquit (1991). Resolving abrupt and high-frequency global changes in the ice-core record, in Global Changes of the Past, R. S. Bradley, ed., Office for Interdisciplinary Earth Studies, UCAR, Boulder, Colo., pp. 175-200. Orth, C. J., M. Attrep, Jr., X. Mao, E. G. Kauffman, R. Diner, and W. P. Elder (1988). Iridium abundance maxima in the upper Cenomanian extinction interval, Geophysical Research Letters 15, 346-349. Orth, C. J., M. Attrep, Jr., and L. R. Quintana (1990). Iridium abundance patterns across bio-event horizons in the fossil record, in Global Catastrophes in Earth History , V. L. Sharpton and P. D. Ward, eds., Geological Society of America Special Paper 247, pp. 45-60. Orth, C. J., M. Attrep, Jr., L. R. Quintana, W. P. Elder, E. G. Kauffman, R. Diner, and T. Villamil (1993). Elemental abundance anomalies in the late Cenomanian extinction interval: A search for the source(s), Earth and Planetary Science Letters 117, 189-204. Philip, J. (1991). L'enregistrement des evenements de la limite Cenomanien-Turonien sur les plates-formes carbonatees de la Tethys, in Colloque International sur les Evenements de la Limite Cenomanien-Turonien, Geologie Alpine, Mem. H. S. No. 17, Grenoble, pp. 105-106. Pindell, J. L., and S. F. Barrett (1990). Geological evolution of the Caribbean Region; A plate-tectonic perspective, in The Geology of North America: H. The Caribbean Region, G. Dengo and J. P. Case, eds., Geological Society of America, Boulder, Colo., pp. 405-432 Pitman, W. C., III (1978). Relation between eustasy and stratigraphic sequences of passive margins, Geological Society of America Bulletin 89, 1389-1403. Pratt, L. M. (1985). Isotopic studies of organic matter and carbonate in rocks of the Greenhorn marine cycle, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 38-48. Rampino, M. R., R. B. Strothers, B. O'Neil, B., and B. Haggerty (1993). Asteroid impacts, mass extinction events, and flood basalt eruptions —An external driver, Stratigraphic Record of Global Change, Abstract Volume, 1990 SEPM Meeting, Pennsylvania State University, pp. 57-58. Raup, D. M., and J. J. Sepkoski (1984). Periodicity of extinctions in the geologic past, Proceedings of the National Academy of Sciences USA 81, 801-805. 

GLOBAL CHANGE LEADING TO BIODIVERSITY CRISIS IN A GREENHOUSE WORLD: THE CENOMANIAN-TURONIAN 68 (CRETACEOUS) MASS EXTINCTION Raup, D. M., and J. J. Sepkoski (1986). Periodic extinctions of families and genera, Science 231, 833-836. Sageman, B. B. (1985). High-resolution stratigraphy and paleobiology of the Hartland Shale Member: Analysis of an oxygen-deficient epicontinental sea, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 110-121. Sageman, B. B. (1992). High-Resolution Event Stratigraphy, Carbon Geochemistry, and Paleobiology of the Upper Cenomanian Hartland Shale Member (Cretaceous), Greenhorn Formation, Western Interior, U. S. , Unpublished Ph.D. thesis, University of Colorado, Boulder, 532 pp. Sageman, B. B., P. B. Wignall, and E. G. Kauffman (1991). Biofacies models for organic-rich facies in epicontinental seas: Tool for paleoenvironmental analysis, in Cycles and Events in Stratigraphy, G. Einsele, W. Ricken, and A. Seilacher, eds., Springer-Verlag, Berlin, pp. 542-564. Sageman, B. B., E. G. Kauffman, P. H. Harries, and W. P. Elder (1994). Cenomanian-Turonian bioevents and ecostratigraphy: Contrasting scales of local, regional, and global events, in Paleontological Event Horizons, C. Brett and G. Baird, eds., Columbia University Press, New York (in press). Schlanger, S. O., and H. C. Jenkyns (1976). Cretaceous oceanic anoxic events: Causes and consequences, Geol. Mijnbouw 55, 179-184. Scholle, P. A., and M. A. Arthur (1980). Carbon isotope fluctuations in Cretaceous pelagic limestones: Potential stratgraphic and petroleum exploration tool, American Association of Petroleum Geologists Bulletin 64, 67-87. Scott, G. R. (1964). Geology of the northwest and northeast Pueblo Quadrangles, Colorado , U.S. Geological Survey, Miscellaneous Geological Investigations Map 1-408. Scott, G. R. (1969). General and engineering geology of the northern part of Pueblo, Colorado, U.S. Geological Survey Bulletin 1262, 131 pp. Sepkoski, J. J. (1990). The taxonomic structure of periodic extinction, in Global Catastrophes in Earth History, V. L. Sharpton and P. D. Ward, eds., Geological Society of America Special Paper 247, pp. 33-44. Sepkoski, J. J., Jr. (1993). Ten years in the library: New data confirm paleontological patterns, Paleobiology 19(1), 43-51. Signor, P. W., III, and J. H. Lipps (1982). Sampling biases, gradual extinction patterns, and catastrophes in the fossil record, in Geological Implications of Impacts of Large Asteroids and Comets on the Earth, L. T. Silver and P. H. Schultz, eds., Geological Society of America Special Paper 190, pp. 291-303. Simberloff, D. S. (1984). Mass extinction and the destruction of moist tropical forests, Zh. Obshch. Biol. 45, 767-778. Strothers, R. B., and M. R. Rampino (1990). Periodicity in flood basalts, mass extinctions, and impacts; A statistical view and a model, in Global Catastrophes in Earth History, V. L. Sharpton and P. D. Ward, eds., Geological Society of America Special Paper 247, pp. 9-18. Thompson, L. G. (1991). Ice core records with emphasis on the global record of the last 2000 years, in Global Changes of the Past, R. S. Bradley, ed., Office for Interdisciplinary Earth Studies, UCAR, Boulder, Colo., pp. 201-224. Villamil, T., and C. Arango (1994). High-resolution analysis of the Cenomanian-Turonian boundary in Colombia: Evidence for sea-level rise, condensation, and upwelling, in Mesozoic-Cenozoic Stratigraphy and Evolution of Northern South America: Implications for Eustasy from a Cretaceous-Eocene Passive Margin, J. Pindell and C. Drake, eds., Geological Society of America Special Paper (in press). Watkins, D. K. (1985). Biostratigraphy and paleoecology of calcareous nannofossils in the Greenhorn marine cycle, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 151-156. Watkins, D. K., T. J. Bralower, J. M. Covington, and C. G. Fischer (1993). Biostratigraphy and paleoecology of upper Cretaceous calcareous nannofossils in the Western Interior Basin, North America, in Evolution of the Western Interior Basin, W. G. E. Caldwell and E. G. Kauffman, eds., Geological Association of Canada Special Paper 39, pp. 521-537. Webb, T., III (1991). The spectrum of temporal climate variability: Current estimates and the need for global and regional time series, in Global Changes of the Past, R. S. Bradley, ed., Office for Interdisciplinary Earth Studies, UCAR, Boulder, Colo., pp. 61-81. Wilde, P., M. S. Quinby-Hunt, and W. B. N. Berry (1990). Vertical advection from oxic or anoxic water from the main pycnocline as a cause of rapid extinction or rapid radiations, in Extinction Events in Earth History, E. G. Kauffman and O. H. Walliser, eds., Springer- Verlag, Berlin, pp. 85-98. Wilson, E. O. (1988). The current state of biological diversity, in Biodiversity, National Academy Press, Washington, D.C., pp. 3-20. Wright, C. W., and W. J. Kennedy (1981). The Ammonoidea of the Plenus Marls and the Middle Chalk, Palaeontological Society Monograph, 148 pp. Zelt, F. B. (1985). Paleoceanographic events and lithologic/geochemical facies of the Greenhorn marine cycle (upper Cretaceous) examined using natural gamma-ray spectrometry, in Fine-Grained Deposits and Biofacies of the Cretaceous Western Interior Seaway: Evidence of Cyclic Sedimentary Processes, L. M. Pratt, E. G. Kauffman, and F. B. Zelt, eds., Society of Economic Paleontologists and Mineralogists, 2nd Annual Midyear Meeting, Golden, Colo., Field Trip Guidebook 4, pp. 49-59.